Rotary sliding vane pump structure



March 2, 1948.-

" A. 1.. STAMSVIK ROTARY SLIDING VANE PUMP STRUCTURE Filed July 29, 1943 v \m///////////// 4 1 FILSJ.

H INVENTOR 1-5:);Z I BY i I I ATTORI I EY Patented Mar. 1948 UNITED STATES PATENT OFFICE no'rAnY snm mc ytzrivm STRUCTURE Alfred L. Stimuli, Pittsburgh, Pa. 7 Application July :9, ms. Serial No. 498,528

This invention relates to apparatus for pumping liquid and more especially liquid such as milk, a service that requires repeated and thorough cleaning of the pump.

Because of the high standard of cleanliness required of milk pumps, an type of pump that cannot be easily and thoroughl cleaned is not suitable for the purpose. Centrifugal pumps have been widely used, but have th disadvantage of low delivery pressure. One of the practical difficulties in using-force pumps has been the fact that stufling boxes cannot be adequately cleaned.

It is an object of this invention to provide an improved pump suitable for milk. The invention is particularly concerned with the construction of the pump rotor and the stuffing box or sea] for preventing the milk, or other liquid, from leaking out of the pump around the drive shaft. The packing of this invention i combined with a vane pump to produce av pump structure that delivers the milk against substantial pressure but can be disassembled easily and has no recesses that are not readily accessible for cleaning,

With this invention the pump vanes slide in a slot that extends completely through the rotorso that there are no pockets in the rotor.' The drive shaft of the pump extends out through a recess in one wall of the housing. The recess opens toward the interior of the housing and holds a sealing ring that is kept under pressure by a spring in the recess. The sealing ring and spring are removed with the pump rotor for- Fig. 3 is a sectional view, with some parts broken away, the section being taken on the line 3-3 of Fig. 1. 1

The pump includes a housing ill having an inlet I l and outlet l2 that communicate with a cylindrical chamber l3 within the housing I 0. The entire front end of the chamber 13 is closed by'a plate N (Fig. 1) that is clamped against a gasket I5 on the rim of the housing by wing nuts 4 Claims. (Cl. 103-137) 2 18 that thread on stud bolts ll extending from the housing 13, 1

There i a recess in the back wall 20 of the chamber IS. The recess is large enough for easy length of the chamber l3. A hub 24 of the rotor 23 turns in the recess withthe cylindrical side wall 2| as a bearing. Vane 25 slide in a diametrical slot or groove 28 (Fig. '2) that extends all the way through the rotor without change of width so that the surfaces of the groove are free of any corners. The groove 26 opens through the front end of the rotor to further facilitate cleaning. The vanes 25 are urged radially by a spring 21, and with the spring 21 are removable from the rotor without disconnecting any fastening means. There are shallow recesses 3| at the inner ends of the vanes for preventing transverse displacement of the spring 21.

The driving connection for the pump includes the hub 24 and a drive shaft 29 that is connected to and in axial alignment with the hub. The drive shaft 29 preferably extends through the end wall 22 as a bearing and has an end 30 shaped for coupling with a source of power. The hub 24 being of considerably larger diameter than the shaft 23 provides a shoulder 32 at the end of the shaft.

An annular sealin ring 33 fits snugly around the shaft 23. The outside diameter of the sealing ring 33 is the same as that of the cylindrical wall 2| and the ring 33 prevents liquid from leaking along the bearing surface 2| beyond the shoulder 32.

The sealing ring 33 is held against the shoulder 32 by a coil spring 34 compressed between the end wall 22 and a washer 35 that'bears against the back of the sealing ring 33. In the preferred embodiment of the invention all parts of the pump are of stainless steel, except the sealing ring 33 and that ring is made of rubber, preferably soft rubber.

The washer 35 has a sloping face in contact with the sealing ring for developing some radial thrust of the sealing ring 33 inward against the shaft 23. During operation of the pump, the

sealing ring 33 remains stationary while the surfaces of the shoulder 32 and shaft 29 that are in contact with the sealing ring move with respect to the ring. These surfaces are sufllciently extensive to effectively seal the pump against "sealing ring on the metal surfaces is light.

Tendency for milk to leak inward along the shoulder 32 is less than if the direction of leakage were radially outward.

It will be apparent that removal of the cover plate It permits the other elements of the pump to be disassembled completely without disconnecting any other fastening means. All of the removable parts of the pump come out through the opening in the front end of the housing. The ease with which the pump can be disassembled is important in a milk pump that requires frequent and thorough cleaning.

After the various elements of the pump have been cleaned, the apparatus can be reassembled with the same facility with which it was taken apart. The spring 34 is first inserted in the recess in the back wall of the housing. The washer 35 is inserted next, and then the sealing ring 33. The vanes 25 are put in the slots 25 of the rotor 23 with the spring 21 between them. The vanes are pushed toward one another to, compress the spring 21 and to reduce the combined radial extent of the vanes to something less than the diameter of the chamber IS. The shaft 29 is then pushed through the chamber i3, through the recess in the back wall 20 and through the openings in the sealing ring 33, washer 35, spring 34, and end wall 22. At the same time the hub 24 is pushed into the bearing 2! and the rotor 23 into the chamber l3 until the side of the rotor contacts with the back wall 20. The parts are then held in assembled relation by putting the plate It over the end of the housing and fastoning the plate in place with the nuts l6.

Terms of orientation are, of course, relative. The illustrated embodiment of the invention can be modified, and some features of the invention can be used without others.

What is claimed is: g

l. A pump comprising a housing in which is a cylindrical chamber, said housing including a removable cover closing the front end of the chamber. the walls of the chamber being straight and free of depressed regions so that the cover forms the entire front wall of the chamber. a rotary pump element in the chamber, a rearwardly extending hub on said pump element. a drive shaft connected with the hub of the pump element and coaxial with. but of smaller diameterthan the hub so that there is a shoulder at the end of the shaft. an inside cylindrical bearing surface for said hub on a wall of the housing, an annular sealing ring beyond said hub and in sealing contact with both the outside surface of the shaft and said cylindrical bearing surface, and a spring her and that is held against endwise displacement by the front and back walls of the chamber, vanes carriedby the rotor, a hub extending from the rotor and fitting into the cylindrical opening as a bearing, a drive shaft connected with the hub and coaxial with the hub, said drive shaft being of smaller diameter than the hub so that there is a shoulder at the connection of the drive shaft and the hub, said rotor, hub and shaft being removable through the front of the housing when the front plate is removed, packing means that is also removable with the rotor, hub and shaft, said packing means including a sealing ring surrounding the shaft and in sealing contact with both the surface of the shaft and the cylindrical bearing surface of theurging the sealing ring against the shoulder, said pump element; drive shaft, sealing ring and spring being rrmovabe through the front of the housing when the cover is removed.

2. A milk pump including a housing in which is -a large-diam ter cylindrical chamber, inlet and outlet conduits having straight and smooth walls and opening directly into the cylindrical chamber, a front plate that covers the end of the cylindrical chamber, the wall of said chamber being straight and free of depressed regions so that said plate comprises the entire front wall of the chamber, said plate being removable to expose the interior of the pump for cleaning, a

, cylindrical opening through the back wall of the opening, a washer at the back of the sealing ring for holding the sealing ring against said shoulder, said washer having a bevel face in contact with the ring, a spring around the shaft, and a surface at the rearward end of the cylindrical bearing for holding the spring compressed against the washer.

3. A milkpump including a housing in which is a large-diameter cylindrical chamber with substantially straight inlet and outlet connections angularly related and located around the periphery of the cylindrical chamber, a plate that covers the end of the cylindrical chamber, the wall of said chamber being straight and free of depressed regions so that said plate comprises the entirefront wall of the chamber, said plate being removable to expose the interior of the pump for cleaning, a cylindrical opening through the back wall of the chamber having an axis eccentric of but parallel to the axis of the cylindrical chamber, a rotor that extends along the full length of the chamber and that is held against endwise displacement by the front and back walls of the chamber. vanes carried bythe rotor, a hub extending from the rotor and fitting into the cylindrical opening as a, bearing, said rotor having a diametrical slot in its front face, which slot extends for the full length of the rotor from said hub, the side walls of said slot providing guide bearings in which the vanes slide, a spring in the slot between the inner ends of the vanes and urging the vanes outward against the cylindrical side wall of the pump chamber, a drive shaft connected with the hub and coaxial with the hub and rotor, and a sealing ring in the cylindrical opening beyond said hub and around ,said shaft, said ring being removable with the shaft through the front of said opening for convenient cleaning.

4. A pump for milk or other beverage that requires thorough and frequent cleaning of the pump, said pump including a housing with a cylindrical chamber t at has a rearward wall in which there is a cylindrical recess of substantial diameter having an axis eccentric of but parallel to the axis of the pump chamber and a central opening through the back wall of the recess, a

rotor having a length substantially equal to that of the cylindrical chamber and a diameter less than that of the cylindrical chamber but greater than that of the recess, a hub at the back of the rotor and secured to the rotor, said hub having a diameter equal to that of the recess and fitting into the recess as a bearing but not extending for the full length of the recess, a drive shaft smaller than the hub and extending from the hub through the central opening in the back wall of the recess, sealing means in the recess and around the shaft, said sealing means being removable from the housing with the rotor and shaft through the front of the housing for convenient cleaning, guides comprising a groove that extends across the rotor, said'groove being of substantially uniform width and open to the front of the rotor, vanes that slide in the groove,

a spring in the groove between the vanes for thrusting the vanes against the cylindrical wall of the pump chamber, a cover plate closing the cylindrical chamber and forming the front wall of the pump chamber, and detachable fastenings securing the cover plate to thehousing.

- ALFRED L. STAMSVIK.

REFERENCES CITED The following references are of record in the mo of this Patent:

Number Re. 22,180 5 2,004,958 2,037.894 2,046,873 736,850 1,535,998 1,719,801 629,796

Number 6 UNITED STATES PATENTS Name Date Davis Aug. 18, 1942 Mitchell June 18, 1935 Grisell Apr. 21, 1936 Garrison July 7, 1936 Hills et a1. Aug. 18, 1903 Hanson et ai. Apr. 28, 1925 Duflield July 2, 1929 ountry Date Great Britain Jan. 20, 1921 Australia Aug. 15, 1941 Great Britain 1893- 

